Cape Breton Island
2 of the 7 encyclopedias on this shelf carry an entry for Cape Breton Island. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
an island of the Dominion of Canada, separated from Nova Scotia, to which Province it belongs, by the narrow Gut or Strait of Canso; area 3,120 square miles. It is of very irregular shape, the Bras d'Or, an almost landlocked arm of the sea (with most picturesque scenery), penetrating its interior in various direc and dividing it into two peninsulas tions, connected by an isthmus across which a canal has been cut. The surface is rather rugged, and only small portions are suited for agriculture; but it possesses much timber, valuable minerals (several coal mines being worked), and the coast abounds in fish. Timber, fish, and coal are exported. The island belonged to France from 1632 to 1763, and Louisburg, its capital, was long an important military post. It was separate from Nova Scotia between 1784 and 1820. Chief town, Sydney. It is a famous summer resort. Near Glace Bay is a powerful long-distance wireless station. Pop. about 85,000.
Aiton's Encyclopedia (1910)
an island of northeastern Nova Scotia . It is separated from the peninsula of the mainland by the Strait of Canso, sixteen miles long and nowhere to exceed two miles in width. A deep bay cuts the island almost in two. The island was settled first by the French, who called it Isle Royale. It was defended by the fortress of Louisburg. The island was ceded to Great Britain in 1763, and was united to Nova Scotia in 1820. Area, 3,120 square miles. Population, about 30,000. The chief town is Sydney. A superior quality of bituminous coal is mined there. See Nova Scotia